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  Subjects -> COMPUTER SCIENCE (Total: 2011 journals)
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COMPUTER SCIENCE (1172 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 872 Journals sorted alphabetically
3D Printing and Additive Manufacturing     Full-text available via subscription   (Followers: 15)
Abakós     Open Access   (Followers: 4)
ACM Computing Surveys     Hybrid Journal   (Followers: 24)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 9)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 13)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 16)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 6)
ACM Transactions on Architecture and Code Optimization (TACO)     Hybrid Journal   (Followers: 9)
ACM Transactions on Autonomous and Adaptive Systems (TAAS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Computation Theory (TOCT)     Hybrid Journal   (Followers: 12)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 3)
ACM Transactions on Computer Systems (TOCS)     Hybrid Journal   (Followers: 18)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 15)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 6)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 2)
ACM Transactions on Economics and Computation     Hybrid Journal  
ACM Transactions on Embedded Computing Systems (TECS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Information Systems (TOIS)     Hybrid Journal   (Followers: 21)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 8)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 9)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 25)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Ad Hoc Networks     Hybrid Journal   (Followers: 11)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Advanced Engineering Materials     Hybrid Journal   (Followers: 26)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 7)
Advances in Artificial Intelligence     Open Access   (Followers: 16)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 6)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 18)
Advances in Computer Science : an International Journal     Open Access   (Followers: 15)
Advances in Computing     Open Access   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 52)
Advances in Engineering Software     Hybrid Journal   (Followers: 27)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 11)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 27)
Advances in Human-Computer Interaction     Open Access   (Followers: 21)
Advances in Materials Sciences     Open Access   (Followers: 16)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 40)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access   (Followers: 4)
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 8)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
Air, Soil & Water Research     Open Access   (Followers: 9)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 6)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1)
Algorithms     Open Access   (Followers: 11)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 5)
American Journal of Computational Mathematics     Open Access   (Followers: 4)
American Journal of Information Systems     Open Access   (Followers: 5)
American Journal of Sensor Technology     Open Access   (Followers: 4)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Animation Practice, Process & Production     Hybrid Journal   (Followers: 5)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 11)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 12)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annual Reviews in Control     Hybrid Journal   (Followers: 6)
Anuario Americanista Europeo     Open Access  
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applied and Computational Harmonic Analysis     Full-text available via subscription   (Followers: 1)
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 13)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Clinical Informatics     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Computer Systems     Open Access   (Followers: 2)
Applied Informatics     Open Access  
Applied Mathematics and Computation     Hybrid Journal   (Followers: 33)
Applied Medical Informatics     Open Access   (Followers: 10)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Soft Computing     Hybrid Journal   (Followers: 15)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Architectural Theory Review     Hybrid Journal   (Followers: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5)
Archive of Numerical Software     Open Access  
Archives and Museum Informatics     Hybrid Journal   (Followers: 135)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Artifact     Hybrid Journal   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 7)
Asia Pacific Journal on Computational Engineering     Open Access  
Asia-Pacific Journal of Information Technology and Multimedia     Open Access   (Followers: 1)
Asian Journal of Computer Science and Information Technology     Open Access  
Asian Journal of Control     Hybrid Journal  
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
Australian Educational Computing     Open Access   (Followers: 1)
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 4)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 11)
Automation in Construction     Hybrid Journal   (Followers: 6)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Basin Research     Hybrid Journal   (Followers: 5)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Biodiversity Information Science and Standards     Open Access  
Bioinformatics     Hybrid Journal   (Followers: 285)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 14)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 18)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 34)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 47)
British Journal of Educational Technology     Hybrid Journal   (Followers: 136)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 2)
CALCOLO     Hybrid Journal  
Calphad     Hybrid Journal  
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 14)
Capturing Intelligence     Full-text available via subscription  
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal   (Followers: 2)
Cell Communication and Signaling     Open Access   (Followers: 2)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 5)
CERN IdeaSquare Journal of Experimental Innovation     Open Access   (Followers: 1)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 14)
ChemSusChem     Hybrid Journal   (Followers: 7)
China Communications     Full-text available via subscription   (Followers: 7)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
CIN Computers Informatics Nursing     Full-text available via subscription   (Followers: 11)
Circuits and Systems     Open Access   (Followers: 15)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
CLEI Electronic Journal     Open Access  
Clin-Alert     Hybrid Journal   (Followers: 1)
Cluster Computing     Hybrid Journal   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 4)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Communication Methods and Measures     Hybrid Journal   (Followers: 12)
Communication Theory     Hybrid Journal   (Followers: 20)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Algebra     Hybrid Journal   (Followers: 3)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 3)
Communications of the ACM     Full-text available via subscription   (Followers: 55)
Communications of the Association for Information Systems     Open Access   (Followers: 18)
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering     Hybrid Journal   (Followers: 3)
Complex & Intelligent Systems     Open Access   (Followers: 1)
Complex Adaptive Systems Modeling     Open Access  
Complex Analysis and Operator Theory     Hybrid Journal   (Followers: 2)
Complexity     Hybrid Journal   (Followers: 6)
Complexus     Full-text available via subscription  
Composite Materials Series     Full-text available via subscription   (Followers: 9)
Computación y Sistemas     Open Access  
Computation     Open Access  
Computational and Applied Mathematics     Hybrid Journal   (Followers: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 2)
Computational and Structural Biotechnology Journal     Open Access   (Followers: 2)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Astrophysics and Cosmology     Open Access   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 11)
Computational Chemistry     Open Access   (Followers: 2)
Computational Cognitive Science     Open Access   (Followers: 2)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Condensed Matter     Open Access  
Computational Ecology and Software     Open Access   (Followers: 9)
Computational Economics     Hybrid Journal   (Followers: 9)
Computational Geosciences     Hybrid Journal   (Followers: 15)
Computational Linguistics     Open Access   (Followers: 22)
Computational Management Science     Hybrid Journal  
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 4)
Computational Methods and Function Theory     Hybrid Journal  
Computational Molecular Bioscience     Open Access   (Followers: 2)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Particle Mechanics     Hybrid Journal   (Followers: 1)
Computational Research     Open Access   (Followers: 1)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computational Science and Techniques     Open Access  
Computational Statistics     Hybrid Journal   (Followers: 14)
Computational Statistics & Data Analysis     Hybrid Journal   (Followers: 30)
Computer     Full-text available via subscription   (Followers: 91)
Computer Aided Surgery     Hybrid Journal   (Followers: 5)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Communications     Hybrid Journal   (Followers: 10)
Computer Engineering and Applications Journal     Open Access   (Followers: 5)
Computer Journal     Hybrid Journal   (Followers: 9)
Computer Methods in Applied Mechanics and Engineering     Hybrid Journal   (Followers: 22)
Computer Methods in Biomechanics and Biomedical Engineering     Hybrid Journal   (Followers: 12)
Computer Methods in the Geosciences     Full-text available via subscription   (Followers: 2)
Computer Music Journal     Hybrid Journal   (Followers: 18)
Computer Physics Communications     Hybrid Journal   (Followers: 6)
Computer Science - Research and Development     Hybrid Journal   (Followers: 8)
Computer Science and Engineering     Open Access   (Followers: 19)
Computer Science and Information Technology     Open Access   (Followers: 13)
Computer Science Education     Hybrid Journal   (Followers: 14)
Computer Science Journal     Open Access   (Followers: 22)

        1 2 3 4 5 6 | Last

Journal Cover Chinese Journal of Catalysis
  [SJR: 0.6]   [H-I: 29]   [2 followers]  Follow
    
   Full-text available via subscription Subscription journal
   ISSN (Print) 1872-2067
   Published by Elsevier Homepage  [3123 journals]
  • Preface to Special Issue on Photocatalysis in China
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Jiaguo Yu


      PubDate: 2018-01-10T10:36:40Z
       
  • A review on TiO2-based Z-scheme photocatalysts
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Kezhen Qi, Bei Cheng, Jiaguo Yu, Wingkei Ho
      TiO2-based Z-scheme photocatalysts have attracted considerable attention because of the low recombination rate of their photogenerated electron–hole pairs and their high photocatalytic efficiency. In this review, the reaction mechanism of Z-scheme photocatalysts, recent research progress in the application of TiO2-based Z-scheme photocatalysts, and improved methods for photocatalytic performance enhancement are explored. Their applications, including water splitting, CO2 reduction, decomposition of volatile organic compounds, and degradation of organic pollutants, are also described. The main factors affecting the photocatalytic performance of TiO2-based Z-scheme photocatalysts, such as pH, conductive medium, cocatalyst, architecture, and mass ratio, are discussed. Concluding remarks are presented, and some suggestions for the future development of TiO2-based Z-scheme photocatalysts are highlighted.
      Graphical abstract image

      PubDate: 2018-01-10T10:36:40Z
       
  • Review on porous nanomaterials for adsorption and photocatalytic
           conversion of CO2
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Yajuan Ma, Zemei Wang, Xiaofeng Xu, Jingyu Wang
      Photocatalytic conversion of “greenhouse gas” CO2 is considered to be one of the most effective ways to alleviate current energy and environmental problems without additional energy consumption and pollutant emission. The performance of many traditional semiconductor photocatalysts is not efficient enough to satisfy the requirements of practical applications because of their limited specific surface area and low CO2 adsorption capacity. Therefore, the exploration of photocatalysts with high CO2 uptake is significant in the field of CO2 conversion. Recently the porous materials appeared to be a kind of superior candidate for enriching the CO2 molecules on the surface of photocatalysts for catalytic conversion. This paper first summarizes the advances in the development of nanoporous adsorbents for CO2 capture. Three main classes of porous materials are considered: inorganic porous materials, metal organic frameworks, and microporous organic polymers. Based on systematic research on CO2 uptake, we then highlight the recent progress in these porous-material-based photocatalysts for CO2 conversion. Benefiting from the improved CO2 uptake capacity, the porous-material-based photocatalysts exhibited remarkably enhanced efficiency in the reduction of CO2 to chemical fuels, such as CO, CH4, and CH3OH. Based on reported recent achievements, we predict a trend of development in multifunctional materials with both high adsorption capability and photocatalytic performance for CO2 utilization.
      Graphical abstract image

      PubDate: 2018-01-10T10:36:40Z
       
  • Improved visible-light photocatalytic H2 generation over CdS nanosheets
           decorated by NiS2 and metallic carbon black as dual earth-abundant
           cocatalysts
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Song Ma, Xingmin Xu, Jun Xie, Xin Li
      CdS nanosheets (NSs) photocatalysts modified with dual earth-abundant co-catalysts of metallic carbon black (CB) and NiS2 were synthesized by a two-step solvothermal/impregnation method. All the experiment results demonstrated that the co-loading of CB and NiS2 could significantly enhance the photocatalytic H2-evolution activity of CdS NSs. The photocatalytic performance of the as-prepared CdS/CB/NiS2 samples was tested under visible light (λ ≥ 420 nm) by using an aqueous solution containing 0.25 mol L−1 Na2S-Na2SO3 as the sacrifice agent. The CdS-0.5%CB-1.0%NiS2 composite photocatalysts exhibited the highest H2-evolution rate of 166.7 μmol h−1, which was approximately 5.16 and 1.87 times higher than those of pure CdS NSs and CdS-1.0%NiS2, respectively. The possible mechanism for the enhanced H2-evolution activity of CdS/CB/NiS2 composite photocatalysts was proposed. The results showed that the enhanced photocatalytic H2-evolution activities could be ascribed to the co-loading of metallic CB and NiS2 as co-catalysts onto the surface of CdS NSs. The excellent synergetic effect between the CB and NiS2 could obviously improve visible light absorption, promote separation of photogenerated electron-hole pairs and boost the H2-evolution kinetics, thus leading to an enhanced activity for H2 evolution. More interestingly, the metallic CB could not only act as a cocatalyst for H2 evolution, but also serve as a conductive electron bridge to promote the charge migration. This work not only demonstrates that loading CB as a co-catalyst is a promising strategy to further boost the photocatalytic activity of CdS/NiS2 composites, but also offers a new mechanistic insight into the construction of highly efficient and stable CdS NSs-based hybrid photocatalysts with dual earth-abundant co-catalysts for photocatalytic applications.
      Graphical abstract image

      PubDate: 2018-01-10T10:36:40Z
       
  • A comparison study of alkali metal-doped g-C3N4 for visible-light
           photocatalytic hydrogen evolution
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Jing Jiang, Shaowen Cao, Chenglong Hu, Chunhua Chen
      Photocatalytic hydrogen production based on semiconductor photocatalysts has been considered as one of the most promising strategies to resolve the global energy shortage. Graphitic carbon nitride (g-C3N4) has been a star visible-light photocatalyst in this field due to its various advantages. However, pristine g-C3N4 usually exhibits limited activity. Herein, to enhance the performance of g-C3N4, alkali metal ion (Li+, Na+, or K+)-doped g-C3N4 are prepared via facile high-temperature treatment. The prepared samples are characterized and analyzed using the technique of XRD, ICP-AES, SEM, UV-vis DRS, BET, XPS, PL, TRPL, photoelectrochemical measurements, photocatalytic tests, etc. The resultant doped photocatalysts show enhanced visible-light photocatalytic activities for hydrogen production, benefiting from the increased specific surface areas (which provide more active sites), decreased band gaps for extended visible-light absorption,land improved electronic structures for efficient charge transfer. In particular, because of the optimal tuning of both microstructure and electronic structure, the Na-doped g-C3N4 shows the most effective utilization of photogenerated electrons during the water reduction process. As a result, the highest photocatalytic performance is achieved over the Na-doped g-C3N4 photocatalyst (18.7 μmol/h), 3.7 times that of pristine g-C3N4 (5.0 μmol/h). This work gives a systematic study for the understanding of doping effect of alkali metals in semiconductor photocatalysis.
      Graphical abstract image

      PubDate: 2018-01-10T10:36:40Z
       
  • Selective adsorption of thiocyanate anions on Ag-modified g-C3N4 for
           enhanced photocatalytic hydrogen evolution
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Feng Chen, Hui Yang, Wei Luo, Ping Wang, Huogen Yu
      Silver-modified semiconductor photocatalysts typically exhibit enhanced photocatalytic activity toward the degradation of organic substances. In comparison, their hydrogen-evolution rates are relatively low owing to poor interfacial catalytic reactions to producing hydrogen. In the present study, thiocyanate anions (SCN−) as interfacial catalytic active sites were selectively adsorbed onto the Ag surface of g-C3N4/Ag photocatalyst to promote interfacial H2-evolution reactions. The thiocyanate-modified g-C3N4/Ag (g-C3N4/Ag-SCN) photocatalysts were synthesized via photodeposition of metallic Ag on g-C3N4 and subsequent selective adsorption of SCN− ions on the Ag surface by an impregnation method. The resulting g-C3N4/Ag-SCN photocatalysts exhibited considerably higher photocatalytic H2-evolution activity than the g-C3N4, g-C3N4/Ag, and g-C3N4/SCN photocatalysts. Furthermore, the g-C3N4/Ag-SCN photocatalyst displayed the highest H2-evolution rate (3.9 μmol h−1) when the concentration of the SCN− ions was adjusted to 0.3 mmol L−1. The H2-evolution rate obtained was higher than those of g-C3N4 (0.15 μmol h−1) and g-C3N4/Ag (0.71 μmol h−1). Considering the enhanced performance of g-C3N4/Ag upon minimal addition of SCN− ions, a synergistic effect of metallic Ag and SCN− ions is proposed—the Ag nanoparticles act as an effective electron-transfer mediator for the steady capture and rapid transportation of photogenerated electrons, while the adsorbed SCN− ions serve as an interfacial active site to effectively absorb protons from solution and promote rapid interfacial H2-evolution reactions. Considering the present facile synthesis and its high efficacy, the present work may provide new insights into preparing high-performance photocatalytic materials.
      Graphical abstract image

      PubDate: 2018-01-10T10:36:40Z
       
  • Boosting the photocatalytic performance of Ag2CO3 crystals in phenol
           degradation via coupling with trace N-CQDs
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Jian Tian, Renyue Liu, Zhen Liu, Changlin Yu, Minchao Liu
      A series of N-CQDs/Ag2CO3 composite crystals (where N-CQDs = Nitrogen doped carbon quantum dots) were prepared by adding different volumes of a solution of N-CQDs during Ag2CO3 crystal growth. Under irradiation from a 350-W Xe lamp light (with optical filter, λ ≥ 420 nm), the performance of N-CQDs/Ag2CO3 in photocatalytic degradation of phenol was evaluated. The as-prepared samples were analyzed by XRD, SEM, TEM, BET, element mapping, UV-vis DRS, FT-IR, XPS, transient photocurrent response and EIS testing. The results showed that after coupling with trace amounts of N-CQDs, both the photocatalytic activity and stability of Ag2CO3 were greatly boosted. The addition of N-CQDs solution influenced the crystallization of Ag2CO3, resulting in a distinct decrease in Ag2CO3 crystal size and an obvious increase in surface area. Moreover, the charge transfer resistance was greatly reduced, and the separation efficiency of photogenerated electrons and holes was strongly promoted. The presence of NCQDs on the surface of the catalysts facilitates the transfer of photogenerated electrons, slowing the photocorrosion rate of Ag2CO3, and then resulting in higher stability than bare Ag2CO3 in degradation. The synergistic effect of the improvement of morphology and charge transfer rate thus accounted for the superior photocatalytic performance of N-CQDs/Ag2CO3.
      Graphical abstract image

      PubDate: 2018-01-10T10:36:40Z
       
  • Photocatalytic degradation of sulfamethazine by graphitic carbon
           nitride-modified zinc molybdate: Effects of synthesis method on
           performance, degradation kinetics, and mechanism
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Jing Zhang, Xuhui Mao, Wei Xiao, Yanfeng Zhuang
      In the present study, zinc molybdate (β-ZnMoO4) and graphitic carbon nitride (g-C3N4)-modified β-ZnMoO4 (β-ZnMoO4/g-C3N4) were prepared to decontaminate aqueous solutions from the antibiotic sulfamethazine (SMZ). Our results revealed that the hydrothermal synthesis method greatly influenced the photocatalytic activity of the resultant catalysts. The pristine β-ZnMoO4 samples obtained under more intensive synthesis conditions (24 h at 280 °C) showed higher photocatalytic activity than that prepared for 12 h at 180 °C (denoted β-ZnMoO4-180). In the case of in situ hydrothermal synthesis of β-ZnMoO4/g-C3N4, a surface-modified sample was only obtained under the reaction conditions of 180 °C for 12 h. Compared with the sheet-like β-ZnMoO4-180 sample, the β-ZnMoO4-180/g-C3N4 composite showed enhanced photocatalytic activity for the degradation of SMZ. By contrast, the hydrothermal reaction at 280 °C caused the gradual decomposition of g-C3N4. It is believed that the structural incorporation of g-C3N4 into β-ZnMoO4 at 280 °C might disrupt the crystal growth, thereby deteriorating the performance of the composite catalysts formed at this temperature. For the composite catalysts prepared by the ultrasonic method, a remarkable increase in the degradation rate of SMZ was only observed at a high g-C3N4 content of 8 mol%. The photocatalytic degradation of SMZ by β-ZnMoO4-180/g-C3N4 composite catalysts followed pseudo-first-order kinetics. Further study of the photocatalytic mechanism revealed that holes and superoxide radicals were the dominant oxidative species in the photodegradation process. The enhanced photocatalytic performance of the composites was attributed to the higher separation efficiency of the photogenerated electron-hole pairs at heterogeneous junctions. The degradation intermediates of SMZ were detected by liquid chromatography-mass spectrometry, from which plausible reaction pathways for the photodegradation of SMZ were proposed. Our results indicated that the synthesis method for g-C3N4 composites should be carefully selected to achieve superior photocatalytic performance.
      Graphical abstract image

      PubDate: 2018-01-10T10:36:40Z
       
  • Construction of Z-scheme Ag3PO4/Bi2WO6 composite with excellent
           visible-light photodegradation activity for removal of organic
           contaminants
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Zhongliao Wang, Taiping Hu, Kai Dai, Jinfeng Zhang, Changhao Liang
      Ag3PO4 has good potential for use in photocatalytic degradation of organic contaminants. However, the activity and stability of Ag3PO4 is hard to sustain because of photocorrosion and the positive potential of the conduction band of Ag3PO4. In this study, A composite consisting of Bi2WO6 nanosheets and Ag3PO4 was developed to curb recombination of charge carriers and enhance the activity and stability of the catalyst. Formation of a Ag3PO4/Bi2WO6 composite was confirmed using X-ray diffraction, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Photoluminescence spectroscopy provided convincing evidence that compositing Bi2WO6 with Ag3PO4 effectively reduced photocorrosion of Ag3PO4. The Ag3PO4/Bi2WO6 composite gave a high photocatalytic performance in photodegradation of methylene blue. A degradation rate of 0.61 min−1 was achieved; this is 1.3 and 6.0 times higher than those achieved using Ag3PO4 (0.47 min−1) and Bi2WO6 (0.10 min−1), respectively. Reactive species trapping experiments using the Ag3PO4/Bi2WO6 composite showed that holes, ·OH, and ·O2 − all played specific roles in the photodegradation process. The photocatalytic mechanism was investigated and a Z-scheme was proposed as a plausible mechanism.
      Graphical abstract image

      PubDate: 2018-01-10T10:36:40Z
       
  • Facile synthesis of Bi12O17Br2 and Bi4O5Br2 nanosheets: In situ DRIFTS
           investigation of photocatalytic NO oxidation conversion pathway
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Wendong Zhang, Xiaoli Liu, Xing'an Dong, Fan Dong, Yuxin Zhang
      Bi12O17Br2 and Bi4O5Br2 visible-light driven photocatalysts, were respectively fabricated by hydrothermal and room-temperature deposition methods with the use of BiBr3 and NaOH as precursors. Both Bi12O17Br2 and Bi4O5Br2 were composed of irregular nanosheets. The Bi4O5Br2 nanosheets exhibited high and stable visible-light photocatalytic efficiency for ppb-level NO removal. The performance of Bi4O5Br2 was markedly higher than that of the Bi12O17Br2 nanosheets. The hydroxyl radical (•OH) was determined to be the main reactive oxygen species for the photo-degradation processes of both Bi12O17Br2 and Bi4O5Br2. However, in situ diffuse reflectance infrared Fourier transform spectroscopy analysis revealed that Bi12O17Br2 and Bi4O5Br2 featured different conversion pathways for visible light driven photocatalytic NO oxidation. The excellent photocatalytic activity of Bi4O5Br2 resulted from a high surface area and large pore volumes, which facilitated the transport of reactants and intermediate products, and provided more active sites for photochemical reaction. Furthermore, the Bi4O5Br2 nanosheets produced more •OH and presented stronger valence band hole oxidation. In addition, the oxygen atoms of NO could insert into oxygen-vacancies of Bi4O5Br2, which provided more active sites for the reaction. This work gives insight into the photocatalytic pollutant-degradation mechanism of bismuth oxyhalide.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Synthesis and photocatalytic hydrogen production activity of the
           Ni-CH3CH2NH2/H1.78Sr0.78Bi0.22Nb2O7 hybrid layered perovskite
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Bing Zhang, Danping Hui, Yingxuan Li, He Zhao, Chuanyi Wang
      The nickel-based complex Ni-CH3CH2NH2-intercalated niobate layered perovskite Ni-CH3CH2NH2/H1.78Sr0.78Bi0.22Nb2O7 was synthesized via a facile in situ chemical reaction method. Using ultrathin H1.78Sr0.78Bi0.22Nb2O7 nanosheets and nickel acetate as precursors. The composition, structure, photophysical properties, and photocatalytic activity for H2 production of Ni-CH3CH2NH2/H1.78Sr0.78Bi0.22Nb2O7 were studied systematically. The photocatalyst loaded with 0.5 wt% Ni exhibited the highest H2 evolution rate of 372.67 μmo/h. This was 0.54 times higher than the activity of the H1.78Sr0.78Bi0.22Nb2O7 nanosheets. The activity of the optimized Ni-CH3CH2NH2/H1.78Sr0.78Bi0.22Nb2O7 was comparable to that of the Pt-loaded sample under the same reaction conditions. The photocatalytic activity of the Ni-CH3CH2NH2/H1.78Sr0.78Bi0.22Nb2O7 was mainly attributed to the excellent separation of photogenerated carriers, after formation of the intercalated complex Ni-CH3CH2NH2. This study provides a facile strategy to synthesize a non-precious metal-loaded photocatalyst for H2 production.
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      PubDate: 2018-01-10T10:36:40Z
       
  • A visible-light-active Au-Cu(I)@Na2Ti6O13 nanostructured hybrid pasmonic
           photocatalytic membrane for acetaldehyde elimination
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Jingjing Yang, Baoshun Liu, Xiujian Zhao
      The present article reports a novel self-standing nanostructured Au-Cu(I)@Na2Ti6O13 plasmonic photocatalytic membrane, which is prepared by a hydrothermal reaction followed by a simple subsequent heat treatment process. The morphological structure, elemental composition, crystalline phases, and optical properties of the membrane were studied in detail by field-emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and ultraviolet-visible spectroscopy. Compared with that of a pure Na2Ti6O13 membrane, the Au-Cu(I)@Na2Ti6O13 membrane displayed much higher photocatalytic activity for the decomposition of acetaldehyde, a typical volatile organic compound, under visible light illumination. It was found that the photocatalytic activity of the Au-Cu(I)@Na2Ti6O13 membrane increased as the amount of Au was increased. The membrane loaded with 2.85 wt% Au showed the highest photocatalytic activity in the decomposition of acetaldehyde of the investigated materials. We found that in the photocatalyst membrane, Na2Ti6O13 acted as a support material, Au displayed plasmonic absorption, and Cu(I) behaved as a co-catalyst. The present membrane materials can avoid the self-aggregation typically observed during the course of photocatalytic reactions. As a result, they can be easily separated, recycled, and reactivated after their practical application, making these functional materials attractive for use in air cleaning applications.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Construction of CuO-modified zeolitic imidazolate framework-9 for
           photocatalytic hydrogen evolution
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Kai Fan, Zhiliang Jin, Hong Yuan, Hongyan Hu, Yingpu Bi
      An efficient CuO-modified zeolitic imidazolate framework-9 (ZIF-9) photocatalyst is successfully prepared at room temperature under mild conditions. It is observed that the ZIF-9/CuO photocatalyst is effective for H2 generation under visible light with sacrificial agent conditions. When the CuO is introduced, the photocatalytic properties of ZIF-9 are greatly improved and when the content of CuO is 40%, the photocatalytic activity reaches a maximum of 78.74 μmol after 5 h. This results from the 200–300 nm cube structure of ZIF-9 being able to adsorb more dye molecules and the CuO, which connects with ZIF-9, greatly improving the electronic transmission efficiency. Moreover, the interaction between the dye molecule Eosin Y (EY) and the catalyst is also studied by transient fluorescence spectroscopy. A series of characterizations, such as SEM, TEM, XPS, XRD, UV-vis, FTIR, transient fluorescence and photocurrent, are conducted, and the results are in good agreement with the experimental result. In addition, the possible reaction mechanism over EY-sensitized ZIF-9/CuO under visible light irradiation is proposed.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Photocatalytic hydrogen evolution activity over MoS2/ZnIn2S4 microspheres
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Bo Chai, Chun Liu, Chunlei Wang, Juntao Yan, Zhandong Ren
      MoS2/ZnIn2S4 composites with MoS2 anchored on the surface of ZnIn2S4 microspheres were synthesized by a two-step hydrothermal process. The obtained samples were characterized by X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, ultraviolet–visible diffuse reflectance absorption spectroscopy, nitrogen adsorption–desorption measurements, photoluminescence spectroscopy, and photoelectrochemical tests. The influence of the loading of MoS2 on the photocatalytic H2 evolution activity was investigated using lactic acid as a sacrificial reagent. A H2 evolution rate of 343 μmol/h was achieved under visible light irradiation over the 1 wt% MoS2/ZnIn2S4 composite, corresponding to an apparent quantum efficiency of about 3.85% at 420 nm monochromatic light. The marked improvement of the photocatalytic H2 evolution activity compared with ZnIn2S4 can be ascribed to efficient transfer and separation of photogenerated charge carriers and facilitation of the photocatalytic H2 evolution reaction at the MoS2 active sites.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Humic acid-mediated visible-light degradation of phenol on
           phosphate-modified and Nafion-modified TiO2 surfaces
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Longhui Zheng, Xiaojuan Yu, Mingce Long, Qilin Li
      Although humic acid (HA) can inhibit TiO2 photocatalysis, it can sensitize TiO2 and induce significant visible-light (VL) activity in phenol degradation. This favorable effect of HA was negligible on phosphate-modified TiO2 (P-TiO2), but significantly stronger on Nafion-modified TiO2 (Nf-TiO2). The reaction rate constants for phenol degradation on Nf-TiO2 increased from (0.003±0.001) to (0.025±0.003) min−1 when the reaction was performed in the presence of 20 mg/L HA. The different effects of HA on P-TiO2 and Nf-TiO2 photocatalysis cannot be attributed to adsorption changes, because the adsorption capacities of P-TiO2 and Nf-TiO2 were only slightly lower than that of TiO2 at an initial HA concentration of 20 mg/mL. Scavenger tests, electron paramagnetic resonance spectroscopy, and H2O2 detection were taken to understand the low VL activity of the P-TiO2/HA suspension. The main active species for phenol degradation in the TiO2 and Nf-TiO2 suspensions were superoxide radicals. There were negligible amounts of superoxide radicals in the P-TiO2/HA suspension, possibly because a direct four-electron oxygen reduction reaction occurred. The better VL activity of Nf-TiO2 was rationalized on the basis of Mott–Schottky and electrochemical impedance plots. Nafion modification resulted in cathodic shifts of the energy band positions, increased electron density, and less resistance to electron transfer across the interface between TiO2 and electrolytes. All these factors facilitated electron transfer and improved the production of active species. Phosphate modification therefore did not improve the VL response of HA sensitized TiO2, and low concentrations of HA can facilitate VL photocatalytic degradation of organic pollutants on Nafion surface-modified TiO2.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Highly photoreactive TiO2 hollow microspheres with super thermal stability
           for acetone oxidation
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Li Liang, Kaining Li, Kangle Lv, Wingkei Ho, Youyu Duan
      TiO2 hollow microspheres (TiO2-HMSs) have attracted much attention because of their high photoreactivity, low density, and good permeability. However, anatase TiO2-HMSs have poor thermal stability. In this study, surface-fluorinated TiO2-HMSs were assembled from hollow nanoparticles by the hydrothermal reaction of the mixed Ti(SO4)2–NH4HF–H2O2 solution at 180 °C. The effect of the calcination temperature on the structure and photoreactivity of the TiO2-HMSs was systematically investigated, which was evaluated by photocatalytic oxidation of acetone in air under ultraviolet irradiation. We found that after calcination at 300 °C, the photoreactivity of the TiO2-HMSs decreases from 1.39 × 10−3 min−1 (TiO2-HMS precursor) to 0.82 × 10−3 min−1 because of removal of surface-adsorbed fluoride ions. With increasing calcination temperature from 300 to 900 °C, the building blocks of the TiO2-HMSs evolve from truncated bipyramidal shaped hollow nanoparticles to round solid nanoparticles, and the photoreactivity of the TiO2-HMSs steady increases from 0.82 × 10−3 to 2.09 × 10−3 min−1 because of enhanced crystallization. Further increasing the calcination temperature to 1000 and 1100 °C results in a decrease of the photoreactivity, which is ascribed to a sharp decrease of the Brunauer–Emmett–Teller surface area and the beginning of the anatase–rutile phase transformation at 1100 °C. The effect of surface-adsorbed fluoride ions on the thermal stability of the TiO2-HMSs is also discussed.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Synthesis, characterization, and activity of a covalently anchored
           heterogeneous perylene diimide photocatalyst
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Jinting Shang, Hanying Tang, Hongwei Ji, Wanhong Ma, Chuncheng Chen, Jincai Zhao
      The consecutive two-photon photocatalytic behavior of perylene diimide (PDI) enables it to catalyze photoreduction reactions that are thermodynamically unfavorable via single-photon processes. In this work, we developed a heterogeneous PDI photocatalyst by covalently binding PDI molecules on the surface of nanosilica. This photocatalyst structure overcomes the intrinsic limitation of the low solubility of PDI, but retains its consecutive two-photon photocatalytic property. Detailed characterization of the photocatalyst by techniques such as thermogravimetric analysis, solid-state nuclear magnetic resonance spectroscopy, and Fourier transform infrared spectroscopy indicated that the PDI molecules were anchored covalently on the surface of nanosilica. The obtained photocatalyst reduced aryl halides under visible-light irradiation in polar organic solvent and in water. The present study provides a promising strategy to realize two-photon activity of PDI in common solvents for photocatalytic applications.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Integrating noble-metal-free NiS cocatalyst with a semiconductor
           heterojunction composite for efficient photocatalytic H2 production in
           water under visible light
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Daochuan Jiang, Liang Zhu, Rana Muhammad Irfan, Lei Zhang, Pingwu Du
      Photocatalytic water splitting is an economical and sustainable pathway to use solar energy for large-scale H2 production. We report a highly efficient noble-metal-free photocatalyst formed by integrating amorphous NiS with a CdS nanorods (NRs)/ZnS heterojunction material for photocatalytic H2 production in water under visible light irradiation (λ < 420 nm). The results show that the photocatalytic H2 production rate reaches an optimal value of up to 574 µmol·h−1 after the loading of NiS, which is more than 38 times higher than the catalytic activity of pure CdS NRs. The average apparent quantum yield is ∼43.2% during 5 h of irradiation by monochromatic 420 nm light. The present study demonstrates the advantage of integration strategies to form not only semiconductor heterojunctions but also photocatalyst-cocatalyst interfaces to enhance the catalytic activity for photocatalytic H2 production.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Enhanced Fenton, photo-Fenton and peroxidase-like activity and stability
           over Fe3O4/g-C3N4 nanocomposites
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Shafaq Sahar, Akif Zeb, Yanan Liu, Naseeb Ullah, Anwu Xu
      We prepared the Fe3O4/g-C3N4 nanoparticles (NPs) through a simple electrostatic self-assembly method with a 3:97 weight ratio to investigate their Fenton, photo-Fenton and oxidative functionalities besides photocatalytic functionality. We observed an improvement of the Fenton and photo-Fenton activities of the Fe3O4/g-C3N4 nanocomposites. This improvement was attributed to efficient charge transfer between Fe3O4 and g-C3N4 at the heterojunctions, inhibition of electron-hole recombination, a high surface area, and stabilization of Fe3O4 against leaching by the hydrophobic g-C3N4. The obtained NPs showed a higher degradation potential for rhodamine B (RhB) dye than those of Fe3O4 and g-C3N4. As compared to photocatalysis, the efficiency of RhB degradation in the Fenton and photo-Fenton reactions was increased by 20% and 90%, respectively. Additionally, the horseradish peroxidase (HRP) activity of the prepared nanomaterials was studied with 3,3,5,5-tetramethylbenzidinedihydrochloride (TMB) as a substrate. Dopamine oxidation was also examined. Results indicate that Fe3O4/g–C3N4 nanocomposites offers more efficient degradation of RhB dye in a photo-Fenton system compared with regular photocatalytic degradation, which requires a long time. Our study also confirmed that Fe3O4/g-C3N4 nanocomposites can be used as a potential material for mimicking HRP owing to its high affinity for TMB. These findings suggest good potential for applications in biosensing and as a catalyst in oxidation reactions.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Synergic effects of CuxO electron transfer co-catalyst and valence band
           edge control over TiO2 for efficient visible-light photocatalysis
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Lina Kong, Xintong Zhang, Changhua Wang, Fangxu Wan, Lan Li
      Bandgap engineering by doping and co-catalyst loading are two primary approaches to designing efficient photocatalysts by promoting visible-light absorption and charge separation, respectively. Shifting of the TiO2 conduction band edge is frequently applied to increase visible-light absorption but also lowers the reductive properties of photo-excited electrons. Herein, we report a visible-light-driven photocatalyst based on valance band edge control induced by oxygen excess defects and modification with a Cu x O electron transfer co-catalyst. The Cu x O grafted oxygen-rich TiO2 microspheres were prepared by ultrasonic spray pyrolysis of the peroxotitanate precursor followed by a wet chemical impregnated treatment. We found that oxygen excess defects in TiO2 shifted the valence band maximum upward and improved the visible-light absorption. The Cu x O grafted onto the surface acted as a co-catalyst that efficiently reduced oxygen molecules to active intermediates (i.e., O2 ·– radial and H2O2), thus consuming the photo-generated electrons. Consequently, the Cu x O grafted oxygen-rich TiO2 microspheres achieved a photocatalytic activity respectively 8.6, 13.0 and 11.0 as times high as those of oxygen-rich TiO2, normal TiO2 and Cu x O grafted TiO2, for degradation of gaseous acetaldehyde under visible-light irradiation. Our results suggest that high visible-light photocatalytic efficiency can be achieved by combining oxygen excess defects to improve visible-light absorption together with a Cu x O electron transfer co-catalyst. These findings provide a new approach to developing efficient heterojunction photocatalysts.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Nanotube array-like WO3/W photoanode fabricated by electrochemical
           anodization for photoelectrocatalytic overall water splitting
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Lingfeng Li, Xiaolong Zhao, Donglai Pan, Guisheng Li
      Photoactive WO3 is attractive as a photocatalyst for green energy evolution through water splitting. In the present work, an electrochemical anodic oxidation method was used to fabricate a photo-responsive nanotube array-like WO3/W (NA-WO3/W) photoanode from W foil as a precursor. Compared with a reference commercial WO3/W electrode, the NA-WO3/W photoanode exhibited enhanced and stable photoelectrocatalytic (PEC) activity for visible-light-driven water splitting with a typical H2/O2 stoichiometric ratio of 2:1 and quantum efficiency of approximately 5.23% under visible-light irradiation from a light-emitting diode (λ = 420 nm, 15 mW/cm2). The greatly enhanced PEC performance of the NA-WO3/Wphotoanode was attributed to its fast electron–hole separation rate, which resulted from the one-dimensional nanotube array-like structure, high crystallinity of monoclinic WO3, and strong interaction between WO3 and W foil. This work paves the way to a facile route to prepare highly active photoelectrodes for solar light transfer to chemical energy.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Photocatalytic Cr(VI) reduction and organic-pollutant degradation in a
           stable 2D coordination polymer
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Fu-Xue Wang, Xiao-Hong Yi, Chong-Chen Wang, Ji-Guang Deng
      A new coordination polymer, Zn(bpy)L (BUC-21), (H2L = cis-1,3-dibenzyl-2-imidazolidone-4,5-°dicarboxylic acid, bpy = 4,4′-bipyridine), has been synthesized under hydrothermal conditions, and characterized by single-crystal X-ray analysis, Fourier transform infrared spectroscopy, thermogravimetric analyses, CNH elemental analysis and UV-Vis diffuse reflectance spectroscopy. BUC-21 exhibited an excellent performance for photocatalytic Cr(VI) reduction with a conversion efficiency of 96%, better than that of commercial P25 (39%), under UV light irradiation for 30 min. BUC-21 could also be used to conduct photocatalytic degradation of organic dyes including methylene blue, rhodamine B, methyl orange and reactive red X-3B. Also, the photocatalytic activity of BUC-21 remained high across a wide pH range from 2.0 to 12.0. It is interesting to note, however, that BUC-21 was unable to achieve simultaneous reduction of Cr(VI) and degradation of an organic pollutant in a mixed matrix, which can be attributed to the competition between Cr(VI) and the organic dyes for access to the photo-excited electrons.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Photocatalytic degradation of Brilliant Green dye using CdSe quantum dots
           hybridized with graphene oxide under sunlight irradiation
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): N. Thirugnanam, Huaibing Song, Yan Wu
      CdSe quantum dots (QDs) hybridized with graphene oxide (GO) are synthesized by a facile chemical precipitation method. The absorption of the CdSe/GO nanocomposite is increased with a significant blue shift with respect to CdSe QDs. The specific surface area of the CdSe/GO nanocomposite is 10.4 m2/g, which is higher than that of CdSe QDs (5 m2/g). The PL intensity of the CdSe/GO nanocomposite is lower than that of the CdSe QDs owing to the inhibition of the recombination of electron-hole pairs in the composite. In Raman analysis, the two bands of the CdSe/GO nanocomposite are shifted to higher wavenumbers with respect to graphene oxide, which is attributed to electron injection that is induced by CdSe QDs into graphene oxide. Using the Brilliant Green dye, the photocatalytic reduction efficiency of CdSe QDs and the CdSe/GO nanocomposite under sunlight irradiation for 90 min are approximately 81.9% and 95.5%, respectively. The calculated photodegradation rate constants for CdSe QDs and the CdSe/GO nanocomposite are 0.0190 min−1 and 0.0345 min−1, respectively. The enhanced photocatalytic activity of the CdSe/GO nanocomposite can be attributed to the high specific surface area and the reduction of electron-hole pair recombination because of the introduction of graphene oxide.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Construction of carbon nitride and MoS2 quantum dot 2D/0D hybrid
           photocatalyst: Direct Z-scheme mechanism for improved photocatalytic
           activity
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12
      Author(s): Yanhui Fu, Zhijun Li, Qinqin Liu, Xiaofei Yang, Hua Tang
      Graphite-like carbon nitride (g-C3N4)-based compounds have attracted considerable attention because of their excellent photocatalytic performance. In this work, a novel direct Z-scheme system constructed from two-dimensional (2D) g-C3N4 nanoplates and zero-dimensional (0D) MoS2 quantum dots (QDs) was prepared through the combination of a hydrothermal process and microemulsion preparation. The morphologies, structures, and optical properties of the as-prepared photocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, transmission electron microscopy, and UV-vis diffuse reflectance spectroscopy. In addition, the photocatalytic performances of the prepared 2D/0D hybrid composites were evaluated based on the photodegradation of rhodamine B under visible-light irradiation. The results demonstrated that the introduction of MoS2 QDs to g-C3N4 greatly enhanced the photocatalytic efficiency. For the optimum 7% MoS2 QD/g-C3N4 photocatalyst, the degradation rate constant was 8.8 times greater than that of pure g-C3N4 under visible-light irradiation. Photocurrent and electrochemical impedance spectroscopy results further demonstrated that the MoS2 QD/g-C3N4 composites exhibited higher photocurrent density and lower chargetransfer resistance than those of the pure g-C3N4 or MoS2 QDs. Active species trapping, terephthalic acid photoluminescence, and nitro blue tetrazolium transformation experiments were performed to investigate the evolution of reactive oxygen species, including hydroxyl radicals and superoxide radicals. The possible enhanced photocatalytic mechanism was attributed to a direct Z-scheme system, which not only can increase the separation efficiency of photogenerated electron-hole pairs but also possesses excellent oxidation and reduction ability for high photocatalytic performances. This work provides an effective synthesis approach and insight to help develop other C3N4-based direct Z-scheme photocatalytic systems for environmental purification and energy conversion.
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      PubDate: 2018-01-10T10:36:40Z
       
  • Author Index for Volume 38 (2017)
    • Abstract: Publication date: December 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 12


      PubDate: 2018-01-10T10:36:40Z
       
  • ZnO-ZrO2 solid solution catalyst for highly selective hydrogenation of CO2
           to methanol
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Tao Zhang
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      PubDate: 2017-12-13T11:36:09Z
       
  • Conversion of biomass to chemicals over zirconium phosphate-based
           catalysts
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Difan Li, Wenxiu Ni, Zhenshan Hou
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      PubDate: 2017-12-13T11:36:09Z
       
  • Recent progress in Ag3PO4-based all-solid-state Z-scheme photocatalytic
           systems
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Ming Ge, Zhenlu Li
      Heterogeneous semiconductor photocatalysis is a promising green technology solution to energy and environmental problems. Traditional photocatalyst TiO2, with a wide band gap of 3.2 eV, can only be excited by UV light and utilizes less than 4% of solar energy. Silver phosphate (Ag3PO4) is among the most active visible-light-driven photocatalysts reported. Unfortunately, unwanted photocorrosion is the main obstacle to the practical application of Ag3PO4. Much effort has been made in recent years to address this issue and further enhance the photocatalytic performance of Ag3PO4. The construction of Z-scheme photocatalytic systems that mimic natural photosynthesis is a promising strategy to improve the photocatalytic activity and stability of Ag3PO4. This brief review concisely summarizes and highlights recent research progress in Ag3PO4-based all-solid-state Z-scheme photocatalytic systems with or without a solid-state electron mediator, focusing on their construction, application, and reaction mechanism. Furthermore, the challenges and future prospects of Ag3PO4-based Z-scheme photocatalytic systems are discussed.
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      PubDate: 2017-12-13T11:36:09Z
       
  • Synergistic photocatalytic effect of porous g-C3N4 in a
           Cr(VI)/4-chlorophenol composite pollution system
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Kai Wei, Kexin Li, Zhenxing Zeng, Yuhua Dai, Liushui Yan, Huiqin Guo, Xubiao Luo
      The photocatalytic reduction of aqueous Cr(VI) to Cr(III) was preliminarily studied using porous g-C3N4 as a photocatalyst under acidic conditions. The observed synergistic photocatalytic effect of porous g-C3N4 on a Cr(VI)/4-chlorophenol (4-CP) composite pollution system was further studied under different pH conditions. Compared with single-component photocatalytic systems for Cr(VI) reduction or 4-CP degradation, the Cr(VI) reduction efficiency and 4-CP degradation efficiency were simultaneously improved in the Cr(VI)/4-CP composite pollution system. The synergistic photocatalytic effect in the Cr(VI)/4-CP composite pollution system can be attributed to the accelerated redox reaction between dichromate and 4-CP by electron transfer with porous g-C3N4.
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      PubDate: 2017-12-13T11:36:09Z
       
  • Electrocatalytic water oxidation by a nickel oxide film derived from a
           molecular precursor
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Fei Li, Hua Li, Yong Zhu, Jian Du, Yong Wang, Licheng Sun
      In this study, we fabricated a NiO x film by electrodeposition of an ethanediamine nickel complex precursor (pH = 11) on a fluorine-doped tin oxide substrate. The resulting film is robust and exhibits high catalytic activity for electrochemical water oxidation. Water oxidation is initiated with an overpotential of 375 mV (1 mA/cm2) and a steady current density of 8.5 mA/cm2 is maintained for at least 10 h at 1.3 V versus the normal hydrogen electrode. Kinetic analysis reveals that there is a 2e−/3H+ pre-equilibrium process before the chemical rate-determining step. The low-cost preparation, robustness, and longevity make this catalyst competitive for applications in solar energy conversion and storage.
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      PubDate: 2017-12-13T11:36:09Z
       
  • Effects of indium on Ni/SiO2 catalytic performance in hydrodeoxygenation
           of anisole as model bio-oil compound: Suppression of benzene ring
           hydrogenation and C–C bond hydrogenolysis
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Xiaofei Wang, Jixiang Chen
      SiO2-supported monometallic Ni and bimetallic Ni-In catalysts were prepared and used for hydrodeoxygenation of anisole, which was used as a model bio-oil compound, for BTX (benzene, toluene, and xylene) production. The effects of the Ni/In ratio and Ni content on the structures and performances of the catalysts were investigated. The results show that In atoms were incorporated into the Ni metal lattice. Although the Ni-In bimetallic crystallites were similar in size to those of monometallic Ni at the same Ni content, H2 uptake by the bimetallic Ni-In catalyst was much lower than that by monometallic Ni because of dilution of Ni atoms by In atoms. Charge transfer from In to Ni was observed for the bimetallic Ni-In catalysts. All the results indicate intimate contact between Ni and In atoms, and the In atoms geometrically and electronically modified the Ni atoms. In the hydrodeoxygenation of anisole, although the activities of the Ni-In bimetallic catalysts in the conversion of anisole were lower than that of the monometallic Ni catalyst, they gave higher selectivities for BTX and cyclohexane as a result of suppression of benzene ring hydrogenation and C–C bond hydrogenolysis. They also showed lower methanation activity. These results will be useful for enhancing carbon yields and reducing H2 consumption. In addition, the lower the Ni/In ratio was, the greater was the effect of In on the catalytic performance. The selectivity for BTX was primarily determined by the Ni/In ratio and was little affected by the Ni content. We suggest that the performance of the Ni-In bimetallic catalyst can be ascribed to the geometric and electronic effects of In.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • In situ preparation of mesoporous Fe/TiO2 catalyst using Pluronic
           F127-assisted sol-gel process for mid-temperature NH3 selective catalytic
           reduction
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Yulin Li, Xiaojin Han, Yaqin Hou, Yaoping Guo, Yongjin Liu, Ning Xiang, Yan Cui, Zhanggen Huang
      An Fe/TiO2 catalyst with uniform mesopores was synthesized using Pluronic F127 as a structure-directing agent. This catalyst was used for selective catalytic reduction of NO with NH3. The catalytic activity and resistance to H2O and SO2 of Fe/TiO2 prepared by a template method were better than those of catalysts synthesized using impregnation and coprecipitation. The samples were characterized using N2-physisorption, transmission electron microscopy, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, and in situ diffuse reflectance infrared Fourier-transform spectroscopy. The results showed that Pluronic F127 acted as a structural and chemical promoter; it not only promoted the formation of a uniform mesoporous structure, leading to a higher surface area, but also improved dispersion of the active phase. In addition, the larger number of Lewis acidic sites, indicated by the presence of coordinated NH3 species (1188 cm−1) and the N–H stretching modes of coordinated NH3 (3242 and 3388 cm−1), were beneficial to mid-temperature selective catalytic reduction reactions.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Copper-catalyzed amination of phenylboronic acids with benzofurazan
           1-oxides
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Manman Wang, Yunyun Li, Fen Wang, Xingwei Li
      CuCl/Phen can catalyze the C–N coupling between arylboronic acid and benzofurazan 1-oxide. This reaction occurred under mild and redox-neutral conditions with benzofurazan 1-oxide as an aminating reagent via ring scission, leading to a bifunctionalized aminonitrobenzene.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • TiO2 composite nanotubes embedded with CdS and upconversion nanoparticles
           for near infrared light driven photocatalysis
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Wanni Wang, Fu Zhang, Chuanling Zhang, Yang Wang, Wei Tao, Sheng Cheng, Haisheng Qian
      We report a colloidal process to coat a layer of TiO2 onto SiO2 composite nanofibers containing embedded CdS and upconversion nanoparticles (UCNPs). The SiO2 composite nanofibers were fabricated by electrospinning. To improve the energy transfer efficiency, UCNPs and CdS nanoparticles were bound in close proximity to each other within the SiO2 matrix. β-NaYF4:Yb(30%),Tm(0.5%)@NaYF4:Yb(20%),Er(2%) core–shell nanoparticles were used as nanotransducers for near infrared light. These nanoparticles exhibited enhanced upconversion fluorescence compared with β-NaYF4:Yb(30%),Tm(0.5%) or β–NaYF4:Yb(30%),Tm(0.5%)@NaYF4 nanoparticles. The morphologies, size and chemical compositions have been extensively investigated using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS), respectively. The TEM images showed that the TiO2 composite nanotubes were embedded with a large amount of UCNPs and CdS nanoparticles. The composite TiO2 nanotubes degraded more than 90% of rhodamine B (RhB) dye during 20 min of irradiation by simulated solar light. In particular, more than 50% of RhB was decomposed in 70 min, under irradiation of near infrared light (NIR). This high degradation was attributed to the full spectrum absorption of solar light, and the enhanced transfer efficiency for near infrared light. The as-prepared nanostructures can harness solar energy, and provide an alternative to overcome energy shortages and environmental protection.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Solid base catalysts derived from Ca-M-Al (M = Mg, La, Ce, Y) layered
           double hydroxides for dimethyl carbonate synthesis by transesterification
           of methanol with propylene carbonate
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Yunhui Liao, Feng Li, Xin Dai, Ning Zhao, Fukui Xiao
      Composite solid base catalysts derived from Ca-M-Al (M = Mg, La, Ce, Y) layered double hydroxides (LDH) were synthesized, characterized and applied to the transesterification of methanol with propylene carbonate. X-ray diffraction analyses of the catalysts show that all of the catalysts were in the form of composite oxides. Compared with the Ca-Al LDH catalyst, the specific surface areas and pore volumes of the catalysts were increased with the introduction of Mg, La or Ce. The catalytic performance of these catalysts increases in the order of Ca-Y-Al < Ca-Al < Ca-Ce-Al < Ca-La-Al < Ca-Mg-Al, which is consistent with the total surface basic amounts of these materials and the formation of especially strong basic sites following modification with Mg and La. The Ca-Mg-Al catalyst shows the highest (Ca+Mg):Al atomic ratio, indicating that it likely contains more unsaturated O2– ions, providing it with the highest concentration of very strong basic sites. The recyclability of these catalysts is improved following the addition of Mg, La, Ce or Y, with the Ca-Mg-Al maintaining a high level of activity after ten recycling trials. X-ray diffraction analyses of fresh and used Ca-Mg-Al demonstrate that this catalyst is exceptionally stable, which could be of value in practical applications related to heterogeneous catalysis.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Selective suppression of toluene formation in solvent-free benzyl alcohol
           oxidation using supported Pd-Ni bimetallic nanoparticles
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Jianwei Che, Mengjia Hao, Wuzhong Yi, Hisayoshi Kobayashi, Yuheng Zhou, Liping Xiao, Jie Fan
      The solvent-free oxidation of benzyl alcohol was studied using supported Pd-Ni bimetallic nanoparticles. Compared with monometallic Pd, the addition of Ni to Pd was found to be effective in suppressing the nondesired product toluene, thereby enhancing the selectivity towards benzaldehyde. This result was attributed to a dual effect of Ni addition: the weakening of dissociative adsorption of benzyl alcohol and the promotion of oxygen species involved in the oxidation pathway.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Synthesis of FER zeolite with piperidine as structure-directing agent and
           its catalytic application
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Weifeng Chu, Fucun Chen, Ce Guo, Xiujie Li, Xiangxue Zhu, Yang Gao, Sujuan Xie, Shenglin Liu, Nan Jiang, Longya Xu
      The synthesis of ferrierite (FER) zeolite using piperidine as an organic structure-directing agent was investigated. X-ray diffraction, X-ray fluorescence, N2-adsorption, and scanning electron microscopy were used to characterize the crystal phases, textural properties, and particle morphologies of the zeolite samples. The crystallization behavior of the FER zeolite was found to be directly related to crystallization temperature. At 150 °C, pure FER phase was observed throughout crystallization. At 160–170 °C, MWW phase appeared first and gradually transformed into FER phase over time, indicating that the FER phase was thermodynamically favored. In the piperidine-Na2O-H2O synthetic system, alkalinity proved to be the crucial factor determining the size and textural properties of FER zeolite. Furthermore, the obtained FER samples exhibited good catalytic performance in the skeletal isomerization of 1-butene.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Preparation of gold clusters on metal oxides by deposition-precipitation
           with microwave drying and their catalytic performance for CO and sulfide
           oxidation
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Ayako Taketoshi, Tamao Ishida, Hironori Ohashi, Tetsuo Honma, Masatake Haruta
      Gold clusters and small nanoparticles supported on metal oxides could be prepared by deposition-precipitation followed by microwave irradiation as a drying method and then calcination. The drying method influenced the size of the Au particles. Au(III) was partly reduced during conventional oven drying, resulting in Au aggregates. In contrast, Au(III) was preserved during microwave drying owing to rapid and uniform heating, and the Au diameter was minimized to 1.4 nm on Al2O3. This method can be applied to several metal oxide supports having different microwave absorption efficiencies, such as MnO2, Al2O3, and TiO2. These catalysts exhibited higher catalytic activities for CO oxidation at low temperature and for selective aerobic oxidation of sulfide than those prepared by conventional methods.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Low-cost and efficient visible-light-driven CaMg(CO3)2@Ag2CO3 microspheres
           fabricated via an ion exchange route
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Jian Tian, Zhen Wu, Zhen Liu, Changlin Yu, Kai Yang, Lihua Zhu, Weiya Huang, Yang Zhou
      CaMg(CO3)2 microspheres were prepared and used as hard templates to fabricate a series of CaMg(CO3)2@Ag2CO3 composite microspheres via a fast and low-cost ion exchange process. The effects of ion exchange time and temperature on the physicochemical properties and photocatalytic activities of the composite microspheres were studied through photocatalytic degradation of Acid Orange II under xenon lamp irradiation. The obtained samples were analyzed by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, UV-vis diffuse reflectance spectroscopy, N2 physical adsorption, and photocurrent tests. The CaMg(CO3)2@Ag2CO3 sample with the highest activity was obtained with an ion exchange time of 4 h and temperature of 40 °C. The degradation rate of Acid Orange II by this sample reached 83.3% after 15 min of light irradiation, and the sample also performed well in phenol degradation. The CaMg(CO3)2@Ag2CO3 produced under these ion exchange conditions showed a well-ordered hierarchical morphology with small particle sizes, which was beneficial to light absorption and the transfer of photoelectrons (e−) and holes (h+) to the catalyst surface. Moreover, the separation of photogenerated·carriers over the composites was greatly improved relative to bare CaMg(CO3)2. Despite the very low content of Ag2CO3 (2.56%), excellent photocatalytic performance was obtained over the CaMg(CO3)2@Ag2CO3 microspheres.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Carbon film encapsulated Fe2O3: An efficient catalyst for hydrogenation of
           nitroarenes
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Yingyu Wang, Juanjuan Shi, Zihao Zhang, Jie Fu, Xiuyang Lü, Zhaoyin Hou
      Iron catalysis has attracted a wealth of interdependent research for its abundance, low price, and nontoxicity. Herein, a convenient and stable iron oxide (Fe2O3)-based catalyst, in which active Fe2O3 nanoparticles (NPs) were embedded into carbon films, was prepared via the pyrolysis of iron-polyaniline complexes on carbon particles. The obtained catalyst shows a large surface area, uniform pore channel distribution, with the Fe2O3 NPs homogeneously dispersed across the hybrid material. Scanning electron microscopy, Raman spectroscopy and X-ray diffraction analyses of the catalyst prepared at 900 °C (Fe2O3@G-C-900) and an acid-pretreated commercial activated carbon confirmed that additional carbon materials formed on the pristine carbon particles. Observation of high-resolution transmission electron microscopy images also revealed that the Fe2O3 NPs in the hybrid were encapsulated by a thin carbon film. The Fe2O3@G-C-900 composite was highly active and stable for the direct selective hydrogenation of nitroarenes to anilines under mild conditions, where previously noble metals were required. The synthetic strategy and the structure of the iron oxide-based composite may lead to the advancement of cost-effective and sustainable industrial processes.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Environmentally friendly, microwave-assisted synthesis of 5-substituted 1
           H-tetrazoles by recyclable CuO nanoparticles via (3+2) cycloaddition of
           nitriles and NaN3
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): R.D. Padmaja, Sourav Rej, Kaushik Chanda
      Recyclable CuO nanoparticles were successfully employed to catalyze the microwave-assisted (3+2) cycloaddition reaction between nitriles and NaN3 to efficiently synthesize 5-substituted 1H-tetrazoles. The salient features associated with this protocol are its cost effectiveness, rapid synthesis, stability, reusability, mild reaction conditions without any additives, high tolerance to various functional groups, and excellent yields under microwave irradiation. This environmentally friendly, microwave-assisted, nanoparticle-catalyzed synthetic methodology is seen as an alternative to conventional procedures that involve Lewis acid catalysts and a simple operation to the privileged scaffold.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Effects of surface physicochemical properties on NH3-SCR activity of MnO2
           catalysts with different crystal structures
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): PiJun Gong, JunLin Xie, De Fang, Da Han, Feng He, FengXiang Li, Kai Qi
      α-, β-, δ-, and γ-MnO2 nanocrystals are successfully prepared. We then evaluated the NH3 selective catalytic reduction (SCR) performance of the MnO2 catalysts with different phases. The NO x conversion efficiency decreased in the order: γ-MnO2 > α-MnO2 > δ-MnO2 > β-MnO2. The NO x conversion with the use of γ-MnO2 and α-MnO2 catalysts reached 90% in the temperature range of 140–200 °C, while that based on β-MnO2 reached only 40% at 200 °C. The γ-MnO2 and α-MnO2 nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area. We found that γ-MnO2 and α-MnO2 possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts. In addition, more chemisorbed oxygen existed on the surface of the γ-MnO2 and α-MnO2 catalysts. The γ-MnO2 and α-MnO2 catalysts showed excellent performance in the low-temperature SCR of NO to N2 with NH3.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Titanocene dichloride: A new green reagent in organic chemistry
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Antonio Rosales Martínez, María Castro Rodríguez, Ignacio Rodríguez-García, Laura Pozo Morales, Roman Nicolay Rodríguez Maecker
      Graphical abstract image

      PubDate: 2017-11-02T03:21:47Z
       
  • Direct construction of sulfenylated pyrazoles catalyzed by I2 at room
           temperature
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Shuang-Hong Hao, Li-Xia Li, Dao-Qing Dong, Zu-Li Wang
      An iodine-catalyzed sulfenylation of pyrazoles at room temperature is described, in which a variety of pyrazoles were well tolerated and the desired products were obtained in good to excellent yields.
      Graphical abstract image

      PubDate: 2017-11-02T03:21:47Z
       
  • High performance ORR electrocatalysts prepared via one-step pyrolysis of
           riboflavin
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Yuxiao Deng, Haixin Huangfu, Shuihua Tang, Jie Li
      Efficient, cost-effective electrocatalysts for an oxygen reduction reaction (ORR) are currently required for fuel cells. In the present work, riboflavin was used as a cheap, nontoxic carbon and nitrogen precursor to prepare Fe–N–C catalysts via one-step pyrolysis in the presence of anhydrous iron chloride. Raman spectroscopy indicated that the catalyst containing nitrogen created a great quantity of defects in the carbon structures, while nitrogen adsorption-desorption isotherms showed that the catalyst was mesoporous. Transmission electron microscopy demonstrated that the Fe–N–C catalyst was composed of very thin, curved and porous graphene layers together with some Fe2O3 nanoparticles, and X-ray diffraction patterns confirmed that the carbon in the catalyst was highly graphitized. X-ray photoelectron spectroscopy indicated that the active sites for the ORR were primarily composed of graphitic nitrogen, although Fe sites also played an important role. The ORR activity of the Fe–N–C catalyst reached a maximum of 4.16 mA cm−2, and its chronoamperometric response was found to decrease by only 3% after operating for 3 h at 0.66 V (vs RHE) in an O2-saturated 0.1 mol L−1 KOH solution. In contrast, a commercial 40 wt% Pt/C catalyst with a loading of 0.2 mgPt cm−2 exhibited an activity of 4.46 mA cm−2 and a 40% loss of response. The electrochemical performance of this new Fe–N–C catalyst was therefore comparable to that of the Pt/C catalyst while showing significantly better stability.
      Graphical abstract image

      PubDate: 2017-11-02T03:21:47Z
       
  • Catalytic performance and synthesis of a Pt/graphene-TiO2 catalyst using
           an environmentally friendly microwave-assisted solvothermal method
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Min Wang, Zhongwei Wang, Lu Wei, Jianwei Li, Xinsheng Zhao
      A Pt/graphene-TiO2 catalyst was prepared by a microwave-assisted solvothermal method and was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, cyclic voltammetry, and linear sweep voltammetry. The cubic TiO2 particles were approximately 60 nm in size and were distributed on the graphene sheets. The Pt nanoparticles were uniformly distributed between the TiO2 particles and the graphene sheet. The catalyst exhibited a significant improvement in activity and stability towards the oxygen reduction reaction compared with Pt/C, which resulted from the high electronic conductivity of graphene and strong metal-support interactions.
      Graphical abstract image

      PubDate: 2017-11-02T03:21:47Z
       
  • Influence of carbon and yttrium co-doping on the photocatalytic activity
           of mixed phase TiO2
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Honglin Gao, Jianmei Liu, Jin Zhang, Zhongqi Zhu, Genlin Zhang, Qingju Liu
      Mixed phase TiO2 photocatalysts doped with C and Y were synthesized by a sol-gel process. The effects of C and Y doping and annealing temperatures on the structural and optical properties, and photocatalytic activity were investigated. We found that both C and Y doping can broaden the absorption spectrum of TiO2 to the visible light region and inhibit recombination of photogenerated electron/hole pairs. The incorporation of Y into the TiO2 lattice inhibited growth of crystalline grains, which increased the specific surface area and enhanced the photocatalytic activity. The photocatalytic performance of the samples was investigated in the photocatalytic degradation of methyl blue under visible light irradiation. The rate of methyl blue degradation over the (C, Y)-co-doped TiO2 sample was much higher than those of undoped TiO2, C-TiO2, and Y-TiO2. Additionally, the apparent first-order rate constant of the co-doped sample was 3.5 times as large as that of undoped mix phase TiO2 under the same experimental conditions. The enhanced photocatalytic activity can be attributed to the synergic effect of (C, Y)-co-doping and the formation of an appropriate crystalline structure.
      Graphical abstract image

      PubDate: 2017-11-02T03:21:47Z
       
  • Coke-tolerant SiW20-Al/Zr10 catalyst for glycerol dehydration to acrolein
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Amin Talebian-Kiakalaieh, Nor Aishah Saidina Amin
      Glycerol dehydration to acrolein over a series of supported silicotungstic acid catalysts (SiW x -Al/Zr y ) was investigated. Characterization results showed that the final catalyst had high thermal stability, a large pore diameter, strong Lewis acidic sites, and a large specific surface area. X-ray photoelectron survey spectra clearly showed peaks attributable to W (W 4f = 35.8 eV), Al2O3 (Al 2p = 74.9 eV), and ZrO2 (Zr 3d = 182.8 eV). The highest acrolein selectivity achieved was 87.3% at 97% glycerol conversion over the SiW20-Al/Zr10 catalyst. The prepared catalysts were highly active and selective for acrolein formation even after 40 h because of the presence of high concentrations of Lewis acidic sites, which significantly reduced the amount of coke on the catalyst surface. Response surface methodology optimization showed that 87.7% acrolein selectivity at 97.0% glycerol conversion could be obtained under the following optimal reaction conditions: 0.5 wt% catalyst, reaction temperature 300 °C, and feed glycerol concentration 10 wt%. Evaluation of a mass-transfer-limited regime showed the absence of internal and external diffusions over pellets of diameter d P < 20 μm. These results show that glycerol dehydration over a strong Lewis acid catalyst is a promising method for acrolein production.
      Graphical abstract image

      PubDate: 2017-11-02T03:21:47Z
       
  • One-step synthesis of graphitic carbon nitride nanosheets for efficient
           catalysis of phenol removal under visible light
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Wang Ding, Suqin Liu, Zhen He
      Graphitic carbon nitride (g-C3N4) nanosheet photocatalysts were synthesized via a facile impregnation-thermal method. The as-prepared materials were characterized and investigated as metal-free photocatalysts for the degradation of phenol in aqueous solution under visible light. Results revealed that the g-C3N4 nanosheets exhibited a 78.9% degradation for phenol after 30 min, which was much faster than that of the pristine g-C3N4. Using Brunauer-Emmett-Teller theory, the surface area of g-C3N4 nanosheets was 103.24 m2/g, which was much larger than that of g-C3N4. The larger surface area increases the contact area of the material with phenol, enhancing the photocatalytic activity. These results highlight the potential application of sustainable metal-free photocatalysts in water purification.
      Graphical abstract image

      PubDate: 2017-11-02T03:21:47Z
       
  • Novel-structured Mo-Cu-Fe-O composite for catalytic air oxidation of
           dye-containing wastewater under ambient temperature and pressure
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Yin Xu, Henan Shao, Fei Ge, Yun Liu
      A novel-structured Mo-Cu-Fe-O composite was successfully prepared by co-precipitation and impregnation method. The properties of the as-prepared samples were determined using X-ray diffraction, temperature-programmed reduction by H2, cyclic voltammetry, and temperature-programmed desorption by O2. The results showed that Mo6+ diffused into the Cu-Fe-O crystal lattice and then formed a new crystalline phase of CuMoO4. The Mo-Cu-Fe-O catalyst had redox properties, and its surface contained active sites for oxygen adsorption. In addition, the catalytic activity of the Mo-Cu-Fe-O composite was evaluated by the degradation of Cationic Red GTL, Crystal Violet, and Acid Red in catalytic wet air oxidation (CWAO) at ambient temperature and pressure. The Mo-Cu-Fe-O catalyst showed excellent activity at basic conditions for the degradation of Cationic Red GTL. High removal efficiencies of 91.5% and 92.8% were achieved for Cationic Red GTL and Crystal Violet, respectively, in wastewater, and the efficiency remained high after seven cycles. However, almost no degradation of Acid Red occurred in the CWAO process. Furthermore, hydroxyl radicals were formed in the CWAO process, which induced the decomposition of the two cationic dyes in wastewater, and the toxicity of their effluents was decreased after degradation. The results indicate that the Mo-Cu-Fe-O composite shows excellent catalytic activity for the treatment of wastewater contaminated with cationic dyes.
      Graphical abstract image

      PubDate: 2017-11-02T03:21:47Z
       
 
 
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